Traditionally, to define a perimeter of a given area to be poured with concrete, a "form board" or perimeter-stopping system using temporary forms is installed. One such temporary form is made of two inch thick (lumber dimension) boards, the widths of which correspond to the thickness of the slab desired, i.e., a four inch thick slab requires 2".times.4" boards, and a six inch thick slab requires 2".times.6" boards, etc. The boards are temporarily installed with forming stakes about the edges of the slab. The top edge of the boards is then set to the desired slab height (i.e., slab thickness) by laser beam or other appropriate site instrument. The concrete is then poured using the top edge of the perimeter forms as a reference. One disadvantage of this system, however, is that conventional concrete surface finishing machines are only able to finish within about six inches of the slab edge. As a result, the outer borders of the slab must be surface finished manually at considerable time and expense.